The technology relates to a secondary battery including an anode that includes a titanium-containing compound, and to a battery pack, an electric vehicle, an electric power storage system, an electric power tool, and an electronic apparatus each of which uses the secondary battery.
Various electronic apparatuses such as mobile phones have been widely used, and it has been demanded to further reduce size and weight of the electronic apparatuses and to achieve their longer lives. Accordingly, small and light-weight secondary batteries that have ability to achieve high energy density have been developed as power sources for the electronic apparatuses.
Note that applications of the secondary batteries are not limited to the electronic apparatuses described above, and it has been also considered to apply the secondary batteries to various other applications. Examples of such other applications may include: a battery pack attachably and detachably mounted on, for example, an electronic apparatus; an electric vehicle such as an electric automobile; an electric power storage system such as a home electric power server; and an electric power tool such as an electric drill.
The secondary battery includes a cathode, an anode, and electrolytic solution. The configuration of the secondary battery exerts a large influence on battery characteristics. Accordingly, various studies have been conducted on the configuration of the secondary battery.
More specifically, in order to improve characteristics such as cycle characteristics, a lithium-titanium composite oxide (Li4/3Ti5/3O4) is used as an active material of an anode, and maleic anhydride is used as an additive of an electrolytic solution (refer to International Publication No. WO 2013/058235 and International Publication No. WO 2013/168821).